Temperate and submediterranean thorn scrub

This habitat is an inland scrub type of about 1.5 to 3 meter high, made up of deciduous shrubs or low trees species of the order Prunetalia, of which many have thorns and many produce berries. These scrubs occur in temperate and submediterranean lowlands and low mountains in Europe, but sometimes are found in dry and rocky localities in higher mountains. The habitat includes šibljak, a deciduous submediterranean scrub type from the Balkan, of which the plant communities are grouped in the order Fraxino orni-Cotinetalia.

The habitat occurs in forest edges and openings, as more-or-less temporary succession stages from grassland to forest, and as hedge structures in cultural landscapes. The scrub is in most cases found on dry to mesic, well-drained, relatively base-rich and poor to moderate nutrient-rich soils. In most cases it is a secondary vegetation, found in sites where Carpinion betuli, Quercion pubescenti-petraeae, Fagion sylvaticae or Aremonio-Fagion are the climax forests, but some stands may grow on more extreme, primary sites, like on shallow, rocky soils and cliffs. The habitat also may occur semi-naturally as part of a mosaic with grassland and forest in extensively grazed areas. On more acidic, nutrient-poor soils in general Rubus scrub (F3.1b) or genistoid scrub (F3.1c) is found, or rather marginally developed mantles with Frangula alnus and Sorbus aucuparia, which can be considered part of the forest habitat.

The composition of the shrub layer varies over the wide range. Most characteristic species in Central and Western Europe are Prunus spinosa, Rhamnus catharticus, Crataegus monogyna and many species of Rosa, including many apomictic species. In some cases non-thorny shrubs may dominate. Saplings of trees are common, and one or a few trees may grow out taller than the scrub formation, indicating succession towards forest. Also the herb layer varies over the range, depending on the soil type and climatic region. It consists of a combination of species from adjacent forest, grassland and tall-herb communities. Climbing herbs are a characteristic feature of this habitat, including Hedera helix, Clematis vitalba and Tamus communis.

In the warmer (submediterranean) parts of the range and on dry, calcareous and south-exposed sites in temperate regions, Prunus mahaleb, Acer monspessulanum, Ligustrum vulgare, Viburnum lantana, Cornus mas, Cotoneaster integerrimus, Cotoneaster tomentosus and Amelanchier ovalis are characteristic species, in sites where forests of the alliance Quercion pubescenti-petraeae are the climax. Some of these shrubs are also typical in šibljak, a deciduous scrubland on shallow soils in the Balkan. Šibljak is supposed to be the primary vegetation in many sites, but it has extended after clearing of forests. Other characteristic deciduous shrubs and low trees of the šibljak are Paliurus spina-christi, Fraxinus ornus, Cotinus coggygria, Syringa vulgaris and Rhamnus intermedia. On Sicily and Corsica Berberis aetnensis is a dominant species of this habitat in the supra-mediterranean mountain belts, where it forms transitions towards oromediterranean hedgehog heath (F7.4b). Berberis hispanica fills such a position in oromediterranean mountains of Spain. However, communities with Berberis cretica in Greece are included in habitat F7.3 (phrygana).

Some Mediterranean species may occur in šibljak, like the evergreen shrubs Ruscus aculeatus and Phillyrea latifolia and the climbers Smilax asper, Clematis flammula and Asparagus acutifolius, but if evergreen shrub species become co-dominant, the scrub is a form of Submediterranean pseudomaquis (habitat F5.3), of which some communities are classified in the order Fraxino orni-Cotinetalia as well. Hippophaë rhamnoides may be one of the thorny shrub species occurring in the thorn scrub habitat, but the physiognomically and ecologically distinct scrubs dominated by Hippophae rhamnoides on xeric, dry, gravelly river terraces, rarely subjected to flooding, are considered as a subset of the alluvial scrub (type F9.1).

Prunus spinosa and other characteristic species may also occur in other scrub types, like those dominated by Rubus species (type F3.1b) or Juniperus species (F3.1a). Buxus sempervirens dominated scrub is included under F5.3. In boreal and subarctic zones Salix species dominate the scrubs on similar soils, and such communities are grouped under habitat F2.3, together with subalpine scrubs. Prunus fruticosa is a shrub that may become dominant in moist grasslands on cacareous soils in the hemiboreal region. For Bulgaria relict stands of this type have been described as a separate habitat type under the Habitats Directive. The syntaxonomical position of these low scrubs is unclear, but they are not considered here as part of thorn scrub. Rubus species may be locally dominant in the habitat, but in other cases they form its own habitat (F3.1b) as a “pre-mantle” formation in front of the thorn scrubs. In more mesic sites and in oceanic regions Corylus avellana may become mono-dominant, forming its own habitat F3.1g. Thorn scrubs in dunes are described under B1.6a and B1.6b.

The habitat has its main distribution in Western and Central Europe and on the Balkan. In the Mediterranean region it is restricted to mountains, to the north the habitat reaches to South-Scandinavia. In cultural landscapes it is one of the most important habitats in terms of diversity and functioning, the latter especially for animal species which find here shelter, breeding sites and food (berries). It is also one of the habitats which increase in dry grassland and agricultural fields after abandonment.

Indicators of quality:

The following aspects may be used as parameters for good quality:

• Diversity of scrub species
• Presence of rare Rosa species
• Absence of non-native species
• Presence of berries in autumn as a food source for mammals and birds
• Presence of flowers in spring as a nectar source for insects

Synthesis of Red List assessment

Confidence in the assessment

Pressures and threats